I get auditory flashbacks, but it doesn't sound like that's what you're experiencing. For example, when cuddling with my boyfriend, I will hear my father's voice, saying things he said in the past.

Auditory hallucinations are not a symptom of PTSD per-say, but they can be caused by severe depression, insomnia, and dissociation, all of which are commonly co-morbid with PTSD.